The Dark Knight

iTrader: (1)

i know our manuals say 33f and 33r but i'm sure we all know higher psi = better mpg... but how high?

the max psi for our tires are 45psi...

i had my tires at ~32psi cold, about a week ago i increased all my tires to ~37psi and my mpg has already jumped up ~0.5mpg...

anyone know how to figure out the optimal psi for best mpg?

should the front tires be slightly more than the rear? or vice versa?

Colin

When you are autocrossing and you have a car that understeers, you typically add air to the rear to balance the car. This has the effect of 'stiffening' the rear compared to the front and helps with the handling (ie lessens rear grip). Since most street cars are set up to understeer, I usually keep the rears 3-5 psi higher than the fronts.

elezam

Remember, you might be getting good gas mileage, but you can also be ruining your tires.

Ikko

And ride quality!

The Dark Knight

iTrader: (1)

good point guys... so what's a good compromise?

elezam

Monitor your tire pressure frequently, every few weeks, and drive slower

The Dark Knight

iTrader: (1)

33 recommended
45 max on tires
im at 37-38

should i leave it at that?

and like Colin said... should i increase the rears a little to maybe 40/41?

jlukja

I found 36F/34R to be the best compromise between fuel economy and ride comfort. I was at 38F/36R for a little while but found it too firm.

RCDave

I run all my tires at max for many years. No unusual wear including the center. May not be the best for handling, but my MPG has always increased 1-2 mpg.

Tires run closer to max run cooler and are less likely to blow due to heat buildup

The Dark Knight

iTrader: (1)

what is the reasoning behind more psi in the fronts?

jlukja

The recommended pressures for my 04 are 32F/30R. I just upped the pressure but kept the same F-to-R pressure differential. I assume that the TSX's front weight bias has something to do with it.

davidspalding

I'll have to try this when I get back to my car. I've been pumping them even-Steven (34-35 psi cold tire inflation) for the past few months. for the idea.

Colin

Exactly. The factory is trying to make it nice and "understeery" and I'm more interested in neutral handling so I think I'm around 34f/37r right now.

jlukja

^^ I should add that I have the Comptech Swaybar so mine feels pretty neutral with the pressures I stated above.

elezam

So does anyone here fill their tires to recommended specs?

Colin

So now you come clean...... For those that don't understand what's going one here, the higher pressure in the rear tires is trying to emulate the effect of the larger rear bar.

davidspalding

Ahhhh,... so with with no add-on components, even-steven inflation will compensate a little for understeer? (Yes, I be noob, learning about these subtleties as I go.)

HeavyDuty

Yeah, me. If I were autocrossing (chalking and reading the sidewall) I would run more in the rear with totally stock suspension, but I'm not and being in my 40's my flabby a$$ likes the stock settings most.

Also, less rattles & squeaks with softer settings.

billabong05

I have my tires set to exactly what my door recommends. 32 psi in the front and 30 psi in the rear. The most the tires get to when warm is 34psi front and 32 psi in the rear. Is this ok? It seems kinda low but I wanted to make sure.

jlukja

No problem there. You can't go wrong with the manufactureres specs.

Colin

No, I'd put about 2-3 PSI more in the rear if you want to mitigate understeer a bit. Of course you don't want to go too far. This is me driving at an autocross a few years ago: http://satoauto.com/video/Auto_x.wmv

HeavyDuty

That was a great video, Colin.

For anyone who hasn't tried it, there is no better way to get in tune with your car and become a faster (read: safer) driver than participating in what Colin showed above.

It was/is so freakin hard for me to remember which way to go when I'm out there. I don't care how many times I walk the track beforehand it's still hard for me. The pointer cones help *a lot* but some clubs don't allow them.

jlukja

^^ faster =/= safer


but, I think I know what you mean.

HeavyDuty

Yeah, I tend to think that if you learn how to handle your car at the limits on a short/long course in a parking lot (or a road course) you'll be *way* better prepared for an emergency situation IRL.

One of my friends in Orlando races at (Lockheed)Martin Sports Car Club & has so for years. Once he was driving around Orlando and a six foot folding table *flew* out of a truck in front of him. What he learned on the track possibly saved his life for he instinctively was able to avoid the table without losing control.

Colin

AND in his spare time as he took evasive action, he was able to measure the length of the table.... That's what you get from high performance driving!

elezam

Great video Colin

HeavyDuty

Yeah, maybe it was a five footer, lol.

Colin

LOL, next thing you know, it will have been a table .... cloth

CL6

Great so when you go off the road and kill yourself because you don't have any traction they can put 'I got good gas mileage' on your tombstone. Urrgghhh...

Legend2TL

I run 38F/35R, been meaning to increase the rear to 38 to see how much understeer is reduced.

My wife's 2003 Honda Pilot, I run 40PSI F/R, +8PSI over the suggested 32 F/R but still under the 44 max for the tire. Besides the mileage I prefer the better handling with the increased pressure.